Release Process

Stable Glibc releases are further maintained in release branches, where they continue to receive backports of bugfixes committed to the main development branch (master). Thus, users will be able to get e.g. 2.16.1 with many bugfixes since fixed in mainline compared to the "main release" 2.16. Releases happen every 6 months around 1st February and 1st August, subject to any regressions or ABI issues. Exact release dates for future releases are decided by consensus and are tracked in their respective release pages. The source tree is frozen 1 month before release to allow time for architecture testing and bug fixes.

2. Distribution Branch Mapping

The following is the mapping of actively supported distribution branches, public or private, with respect to the upstream glibc branches.

Distribution

Branch

Red Hat Enterprise Linux 5

2.5

Red Hat Enterprise Linux 6

2.12

Red Hat Enterprise Linux 7

2.17

Fedora 21

2.20

Fedora 22

2.21

Fedora 23

2.22

Fedora 24

2.23

Fedora 25

2.24

Fedora 26

2.25

Fedora 27

2.26

Fedora 28 (tentative plan)

2.27

IBM Advance Toolchain 9.0

2.22

IBM Advance Toolchain 10.0

2.24

IBM Advance Toolchain 11.0

2.26

3. General policy

Each release branch owns a Git ref namespace release/VERSION/, recommended structure being release/VERSION/master for development, while tags are made under the common scheme glibc-VERSION.REVISION (i.e. glibc-2.11).

Normally, a release branch is forked off master after the stable version is tagged (usually, commits intended to update the version appear for few days after the version is tagged and the release branch would diverge only right before version.h is updated to reflect start of development for next main version), and consists purely or almost purely of cherry-picked fixes committed to the master branch.

Each branch is maintained by a single release manager, who has the responsibility of maintaining the particular stable branch, has final say on what goes in and tags further revisions on the branch. The branch is expected to receive many liberally merged bugfixes from master at the beginning when many new bugs are found, then become more conservative and decrease the rate of back-ports as most major problems are solved and the branch is being propagated to more mature distribution versions. Usually, the interested committers have discretion over which bugfixes to pick for back-porting, but if discussion arises, general consensus of the community is sought, the default choice being to err on the conservative side. Patch backports to stable branches are discussed on libc-stable, and any patch on master that doesn't change ABI or API is immediately suitable for backporting to a stable branch. It is polite to post your backport to libc-stable (in parallel with your commit) and explain the reason for the backport; this helps distro maintainers decide if they want to sync to get the fix.

It is best if a release manager volunteers, and is agreed by the community, at the start of mainline development leading to the new release (for example, a 2.17 release manager should be agreed around the time 2.16 is released). If a release manager is agreed at that time, they may then agree a release timetable with the community for the next stable release and branch. If you would like to try this out, and especially if you have some interest in the branch well-being (e.g. you are distro maintainer who will base a distro branch on top of this release), feel free to just suggest yourself on libc-alpha!

Each branch has so-called interested parties, usually glibc maintainers in distributions where the particular branch is being used; tagging revisions on the release branches should result of consensus between the maintainer and interested parties - one workable model is that the maintainer suggests that he wants to release and other people check if they are happy with the set of patches included and the timing is fine-tuned; if a release is important for one of the parties (e.g. distribution nearing a release), they can suggest a release of new revision as well if it is meaningful.

Anyone can suggest a fix committed on master (unless it's N/A for master for some reason - in that case, discussion about the patch is expected) to be included in a release branch, either by marking it by an appropriate keyword in bugzilla, or cherry-picking it themselves and sending a pull request. Developers with glibc commit permissions can in general push into any release branch, but they are expected to execute reasonable judgement and follow the branch policies. All cherry-picked commits should be created using git cherry-pick -x to indicate the id of the original commit in the commit message (see details on cherry-picking in Git). Always aim at having one cherry-picked commit for one original commit.

Note that the above process is still in flux and may change based on our experience with it. Particular release branches may fine-tune these policies in different ways, though the spirit should stay the same. Try to pay attention to what your past (or concurrent) predecessor release managers have done, and learn from their examples and mistakes. It is expected to have discussion on new policies (even per-branch ones) and any unusualities on libc-alpha.

Final words: Always keep in mind the GNU copyright discipline.

4. New Release Manager [REQUIRED]

Each release manager should have or gradually obtain:

Push access to git.sourceware.org. [REQUIRED]

A published (preferably well cross-signed) PGP key for signing release tags. [REQUIRED]

Have your PGP key in the list of glibc releasers on gnu.org; see below. [RECOMMENDED]

5. Step-by-Step Release

Process

Full Release

Point Release

When?

Development

New development

Backports

6 months before release

Freeze

1 month before release

Translations

Right after freeze

Testing

All through the freeze

RM Testing

All through the freeze

News/Contrib

Just before release

Regenerate

Just before release

Final translations

Just before release

Tag

At release

Branch

At release

Upload release

At release

6. Release Steps

6.1. Development [REQUIRED] (6 months before release)

Active development is carried out on master.

Create wiki page for the coming branch from Release/X.Y template, and link it here at the top of the page. [REQUIRED]

The release branches receive backports from master:

For every new point release e.g. X.Y.N create a new section in NEWS which will contain the new set of fixed bugs for the point release. Make sure that you copy the bug number and description entry from the NEWS file during the backport (for new-style auto-generated bug lists), and otherwise just the bug number (for old-style releases with bug number lists).

Work through the bugzilla issues tagged with the keyword associated with the release branch you maintain. For example if you are maintaining X.Y and a bug has the keyword glibc_X.Y, then that means the fix for this bug should be backported to glibc_X.Y. As the release manager you have two options, accept the change and carry out the backport or reject the change. If you reject backport you must remove the glibc_X.Y keyword and document in the issue why the bug was rejected for backport to glibc release branch X.Y.

6.2. Freeze [REQUIRED] (1 month before release)

A general development freeze should be declared some time before release.

During this period before the release, the release manager may ask committers to limit commits to master. Changes to avoid include:

Anything requiring ports architecture maintainers to update their ports (the period should allow them to catch up with any updates left from the previous development).

Anything changing the public ABI and so requiring check-abi updates on each architecture, or adding libm tests that will require ulps updates on each architecture (again, the period allows for architecture maintainers to update these files and get them ready for the release).

Some time before the release, regenerate libc.pot. See Regeneration for details.

If there are any new messages or changes to messages since the last libc.pot submitted to the Translation Project, generate a snapshot tarball. Submit it to the Translation Project so translations can be updated before the release.

The step by step process is like this:

Regenerate libc.pot, review the changes and check it in.

Generate tarballs using make dist.

Upload snapshot to alpha.gnu.org using gnupload e.g. ./gnupload --to alpha.gnu.org:glibc glibc-2.20-546-ga8db092.tar.bz2 (Careful that absolute path to tarball is also appended on the remote host). Do not upload to ftp.gnu.org, only official releases should be uploaded there.

6.4. Incorporate translations [REQUIRED] (All through the freeze)

Monitor the libc-alpha mailing list for notifications of new translations being available. The subject is of the form "New $LANG PO file for 'libc'". The maintainer can then incorporate the translation by running the following command in the build directory:

make -r PARALLELMFLAGS="" -C ../po objdir=`pwd` update-translations

Once the command completes, monitor the diff and push it to git. Finally, send a message to the list indicating which language translations have been merged.

6.5. Testing [REQUIRED] (All through the freeze)

Architecture maintainers should test glibc for their architectures using the testsuite to make sure it is working well (the release manager should ask them to do so). [REQUIRED]

6.7. News [RECOMMENDED] (Just before release)

Shortly before the release, look for any significant user-visible changes not mentioned in the NEWS file and add them to that file.

6.8. Insert list of fixed bugs in NEWS [REQUIRED]

There should be a placeholder at the bottom of the NEWS file section for the new release:

The following bugs are resolved with this release:
[The release manager will add the list generated by
scripts/list-fixed-bugs.py just before the release.]

Replace that last paragraph by the (UTF-8) output of scripts/list-fixed-bugs.py (with version number as argument, e.g. scripts/list-fixed-bugs.py 2.123) and commit the result.

6.9. Update manual/contrib.texi [RECOMMENDED]

Shortly before the release, check that the contributors for this releases are given credit in manual/contrib.texi.

6.10. Update manual/install.texi [RECOMMENDED]

Shortly before the release, test building with the most recent GCC release and update the statement in manual/install.texi about the most recent GCC release with which building glibc was tested. Similarly for binutils and texinfo. Regenerate the INSTALL file.

6.11. Regenerate [REQUIRED]

After testing and shortly before the release (perhaps a week before) regenerate all files that need regeneration. See Regeneration.

Please note that make dist-prepare is not sufficient for this use case since it should regenerate files even if the timestamps are up to date.

6.13. Tag [REQUIRED] (At release)

Update RELEASE to "stable" and VERSION to "X.Y" e.g. "2.16" in version.h.

Update __GLIBC_MINOR__ in include/features.h.

Create signed tag glibc-X.Y or glibc-X.Y.Z and push it to the public glibc repository

Create the tag using git tag -s; verify it's signed by the PGP key you want to sign it with.

The tag comment shall contain the full announcement you are about to send out as the last step.

Push the tag git push origin glibc-X.Y to the remote server for everyone to reference.

6.14. Branch [REQUIRED] (At release)

This step is skipped for point releases.

Branch the release from master:

Create a release/X.Y/ branch from master on glibc using the tag made in the previous step.

Development starts for the next major release:

Update RELEASE to "development" and VERSION e.g. "2.16.90" in version.h on master.

Create a section for the next release in the NEWS file:

Version 2.NN
Major new features:
[Add new features here]
Deprecated and removed features, and other changes affecting compatibility:
[Add deprecations, removals and changes affecting compatibility here]
Changes to build and runtime requirements:
[Add changes to build and runtime requirements here]
Security related changes:
[Add security related changes here]
The following bugs are resolved with this release:
[The release manager will add the list generated by
scripts/list-fixed-bugs.py just before the release.]

6.15. Upload release [REQUIRED] (At release)

The release manager creates tarballs and sends announcements.

Create a tarball of the tagged release.

Use make dist in a build tree - it will generate couple of ../glibc*tar* files.

Verify the tarballs are sensible, try to build the glibc from the tarball (e.g. using it as source for your distribution package).

Sign + upload your tarballs to ftp.gnu.org - see below for a gnupload invocation that can make your life easier.

Ask the Bugzilla Admin Team to update the sourceware bugzilla to add a new keyword to track this release e.g. glibc_M.N.

Ask the Bugzilla Admin Team to update the sourceware bugzilla to add a new version and milestone to track the next release e.g. M.N. Versions and milestones are best added when development starts for a release, not after branching (for example, create those for 2.17 at the time 2.16 branches), but if the newly branched version does not already have them, then they should be created at that time.

FROM: Release Manager <you@exmaple.com>
SUBJECT: The GNU C Library version X.Y is now available
The GNU C Library
=================
The GNU C Library version X.Y is now available.
The GNU C Library is used as *the* C library in the GNU system and
in GNU/Linux systems, as well as many other systems that use Linux
as the kernel.
The GNU C Library is primarily designed to be a portable
and high performance C library. It follows all relevant
standards including ISO C11 and POSIX.1-2008. It is also
internationalized and has one of the most complete
internationalization interfaces known.
The GNU C Library webpage is at http://www.gnu.org/software/libc/
Packages for the X.Y release may be downloaded from:
http://ftpmirror.gnu.org/libc/
http://ftp.gnu.org/gnu/libc/
The mirror list is at http://www.gnu.org/order/ftp.html
NEWS for version X.Y
====================
<Cut and paste from NEWS file>
Release Notes
=============
https://sourceware.org/glibc/wiki/Release/X.Y
Contributors
============
This release was made possible by the contributions of many people.
The maintainers are grateful to everyone who has contributed
changes or bug reports. These include:
<git shortlog --summary -w72 glibc-(Previous X.Y tag).. | sed -e 's,^.*\t,,g'>

Also announce the release in the news feed of the Savannah site for aggregation at planet.gnu.org. This involves logging into Savannah, clicking My Groups, then GNU C Library, and then News and Submit. Then get one of the project stewards to accept the submission (same process but click Manage instead of Submit and the steward reviews the text and clicks Submt

Announce it on LinkedIn and LinkedInglibc developers group. Post only a single line comment about the release and include a link to the libc-alpha annoucement (avoids moderation delays for posting a large post). If your post doesn't show up then get a project steward to approve the post since it's probably stuck in moderation.

Ask the Web Admin Team to update the glibc homepage at gnu.org with a NEWS item that links to the release announcement (main index.html and download.html with examples). Also have them updated the online manual to the latest version.